Means for applying a sonic or ultrasonic transducer system to a surface to prevent deposition of materials thereon



...11. @QQDMMN ET AL 3945517 MENS FOR APFLYING SONIC OR ULTRASONC TRNSDUCER SYSTE' TO A SURFACE TO PREVENT DEPOSITION OF MATERIALS THEREON John Edward GGDDW? @Y md Araba? @am ma@ .a. E. Goommm ET AL 3,468,517 MEANS FOR APPLYING A SONIC OR ULTRASONC TRANSDUCER SYSTEM TO A SURFACE TO PREVENT DEPOSITION OF MATERIALS THEREON Filati Gai. l0, i967 3 Sheets-Sheet 2 Sqn. 23, 1969 E. GoQDMAN ET AL 3,468,51 7

MEANS POR APPLYING A SONIC OR ULTRASONIC TRANSDUCER SYSTEII T0 A SURFACE TO PREVENT DEPOSITION 0F KATERIALS THEREON Filed Oct. 10. 1967 3 Sheets-Sheet 5 rm ///l [TTI N/ M 4 M N/ W /D mi; l bvv Cr Q5 /CT/G 7 /A/l/E/VTOS John Edward GOODMAN and Arthur GRANGE United States Patent O 3,468,517 IVIEANS FOR APPLYING A SONIC OR ULTRA- SONIC TRANSDUCER SYSTEM TO A SUR- FACE TO PREVENT DEPOSITION OF MA- TERIALS THEREON vlohn E. Goodman, Rawdon, and Arthur Grange, Ilkley, 5

U.S. Cl. 259-2 Claims ABSTRACT OF THE DISCLOSURE Anv apparatus for transmitting sonic and ultrasonic vibrations to a pipe or container carrying a uid to prevent deposition of the fluid on the inner surface of the pipe or container, the apparatus comprising a transducer and probe mounted together coaxially in abutting, end-toend relationship, the probe consisting of a resonant member of substantial mass and having secured to its side over a minimal area near the end furthest from the transducer one end of a rigid coupling member which extends from the probe at least initially in a direction at right angles to the longitudinal axis of the transducer-probe assembly, the other end of the coupling member being secured to the surface preferably at right angles to the longitudinal axis of the pipe or container at the point of securing. A plurality of transducer-probe assemblies may be secured to the surface by a common coupling member, or the assembly and coupling member may -be located inside a v container.

This invention relates to means for applying a sonic or ultrasonic transducer system to a surface or surfaces so as to transmit to it or them high frequency vibrations suflicient to substantially prevent deposition on them of materials which would otherwise tend to adhere to such surface or surfaces.

In particular the invention concerns the coupling of the probes or resonant members of a sonic transducer system to apparatus (eg. pipes or plates) which have large surface areas all of which are required to be soniiied at high intensity to prevent deposition on these surfaces of materials held thereby or passing in contact therewith.

Difficulties have been encountered up till now in coupling the transducer systems to the apparatus so that large surfaces can be adequately sonied, it having been thought necessary to couple a number of probes of the system to the surface at widely spaced intervals to ensure proper transmission of the vibrations to all parts of the surface.

The sonication of a liquid by means of a stainless steel probe does not disturb the high Q of the transducers as the coupling coeicient is dependent on the acoustic impedances of the two media (i.e. metal and liquid), these being very different and resulting in a relatively small transfer of energy to the liquid. As is well known in the art, Q is a quality factor being the ratio of the energy stored in the mass over the energy dissipated in the load per cycle.

To those knowledgeable in the art it will be seen that a low energy transfer cannot result in a damping of the resonant system and therefore the high Q will be maintained.

The coupling of transducers to large metal structures, pipes and ilat plates associated with heat exchangers must be undertaken such as not to disturb the resonant system.

The coupling must be achieved in such a manner as to preserve the natural resonant frequency of the probe and its attendant high Q.

ICC

The apparatus proposed according to the invention consists of a transducer and probe mounted together in coaxial, abutting, end-to-end relationship. The probe consists of a resonant material of substantial mass. One end of a rigid coupling member is secured to the side of the probe over a minimal area near the end furthest from the transducer and this rigid coupling member extends in a direction substantially at right angles to the longitudinal axis of the transducer-probe assembly. The other end of the coupling member is secured at right angles to the longitudinal axis of the pipe or of the container carrying the uid which is to be subjected to the sonic and/or ultrasonic vibrations. The aforesaid probe assembly may be used as a unitary device for attachment to the surface of a pipe or container or a plurality of transducer-probe assemblies may be coupled by a common coupling member and secured to the surface. The transducer-probe assembly or assemblies may be located inside of the pipe or container. This coupling member may be of any suitable material, for example a metal plate or bar, and the transducers may be of the piezoelectric or magnetostrictive kind. The coupling member will be secured to the part to be vibrated so as to transmit the vibrations thereto in the most efiicient direction.

In order that the invention may be fully and clearly comprehended, the same will now be described with reference to the accompanying drawings which are merely diagrammatic -but which illustrate several applications of the invention suited to dilferent conditions and circumstances.

In these drawings:

FIGURE l illustrates how the probe of a transducer device can be coupled to a pipe of smaller diameter than that of the probe;

FIGURE 2 illustrates how the probes of two transducer devices can be coupled to a pipe by a common coupling member and how the pipe may be coiled and may have additional transducer devices coupled in like manner at intervals along the length of the pipe;

FIGURE 3 represents a fragmentary plan of the additional transducer device shown in FIGURE 2;

FIGURE 4 illustrates how the probe of a transducer device can be coupled to a pipe of larger diameter than that of the probe;

FIGURE 5 illustrates in plan how a plurality of transducer devices can be arranged around a pipe and have their probes coupled to the pipe by a common coupling member;

FIGURE 6 illustrates how a transducer device may be located inside a container or hollow member with its probe secured to the bottom of the wall of the container by a coupling member; and

FIGURE 7 illustrates a variation of FIGURE 6 in which the probe is coupled to the container Wall part way along the latter.

Referring to these dawings, there is shown in FIG- URE 1 a transducer device comprising transducers T and a probe P. Also shown is a portion of a pipe 1 through which may flow a liquid. The transducer device has its longitudinal axis parallel to the pipe axis and the end of the probe furthest from the transducers is secured by a coupling member CA to the pipe. This member CA is a metal plate or bar and one end is curved and welded to the curved face of the cylindrical probe, while the other end is formed with a hole through which the pipe passes, the pipe being welded thereto.

The dimensions of the plate CA will be decided by the sizes of the probe and of the pipe and the requirements and circumstances of the plant or installation in which the invention is to be used, but as an example it may be said that with a probe of 8 cms. diameter the plate may be approximately 4 cms. wide and 1.5 cms. thick While its length may be anything up to 60 cms. or even more as required. The plate thus forms a substantially rigid coupling capable of transmitting the vibrations as indicated by the double-headed arrows. Also, since the plate is only secured around approximately one-quarter of the circumference of the probe, it does not have any serious damping effect upon the probe vibrations.

In the arrangement of FIGURE 2, the pipe 1 passes through and is welded to the coupling member as before, but in this case the plate CB extends on both sides of the pipe and each end is Welded to the probe P of a transducer device. This arrangement enables stronger vibrations to be transmitted to the pipe and gives a mechanical balance. Moreover the vibrations may be transmitted to a considerable length of the pipe even if it is not straight, for example if it is coiled as illustrated.

Where the length of the pipe, whether coiled or otherwise shaped, is to great for receiving sucient vibration throughout its length from a transducer system acting on one part of the pipe, one or more additional transducer devices may be coupled to the pipe in accordance with this invention at suitable intervals, say at every third coil. In FIGURE 2 an additional transducer device has its probe coupled to the pipe by a looped coupling bar CC whose ends are welded to the probe and pipe as before. In this case, the axes of the probe and pipe are mutually perpendicular but the -bar extends from the probe at right angles to the probe axis and the vibrations from the probe are still transmitted to the pipe in the axial direction of the latter as indicated by the double-headed arrows.

In FIGURE 4 the pipe 2 is of larger diameter than that of the probe and the coupling plate CD is welded to a portion of the pipe circumference.

In FIGURE 5 the coupling member CE is in the form of a spider or four-armed plate to each arm of which is welded the probe of a transducer device, the pipe 1 passing through a central hole and being welded to the plate. This gives a still better balanced application of vibrations than the FIGURE 2 arrangement and enables better use to be made of the high Q of the transducer devices.

In a still further embodiment of the invention illustrated in FIGURE 6 and suitable for preventing crystallisation deposits on the wall of a canister or thimble or other container, a canister 3 is suspended in a vessel containing a fluid material M and a transducer deviceis mounted within the canister by coupling its probe P to the bottom edge of the canister wall by means of a metal ring-shaped coupling member CF. This ring coupling is Welded to the circumference of the probe so as to extend at right angles to the direction of vibration of the probe and is substantially rigid. For example, an 8 cm. diameter probe might be used with a 13 cm. diameter canister, but a larger canister might need a larger probe and the thickness of the coupling might be of the order of 1.5 cm.

A modiiication of this arrangement is represented in FIGURE 7 wherein the coupling ring CF is used to couple the probe to the canister Wall part Way up the wall. In-

.4 stead of being ring shaped, the coupling member CF might be in the shape of a bar spanning the canister and welded at its ends to the canister.

For best results in the use of the invention the contact area of the coupling member with the side of the probe should be fairly small compared with the area of the end surface of the probe. Also, the greater the distance between the probe and the surface to be vibrated and the greater the mass of this surface, so the more rigid should be the coupling member and the smaller should be its contact area with the probe in order to transmit the vibrations with the maximum efficiency.

We claim:

1. An apparatus for transmitting sonic and ultrasonic vibrations to a surface to substantially prevent deposition on said surface of a fluid material in contact therewith, comprising in combination:

a transducer;

a probe mounted coaxially with said transducer, with the driving face of said transducer in abutting, endto-end relation to said probe;

said probe consisting of a resonant member of substantial mass;

and a substantially rigid coupling member secured to said surface and secured also to the side of said probe over a minimal area thereof at the end thereof furthest from said transducer and so as to extend from said probe at least initially in a direction substantially at right angles to the direction in which said resonant member vibrates.

2. An apparatus as claimed in claim 1, wherein said surface to -be vibrated consists of a pipe through which a fluid material is to iiow and said coupling member is secured to said pipe so as to extend substantially at right angles to the longitudinal axis of said pipe at the securing position.

3. An apparatus as claimed in claim 2, wherein at least two of said transducer-probe assemblies are arranged around said pipe and the ends of the probes which are furthest from the transducers are secured to said pipe by a common coupling member.

4. An apparatus as claimed in claim 1, wherein said surface to be vibrated consists of a container for contacting said uid material and said transducer-probe assembly is located inside said container with said coupling member secured to the wall thereof.

References Cited UNITED STATES PATENTS 3,154,890 ll/l964 Lemelson.

WALTER A. SCHEEL, Primary Examiner JOHN M. BELL, Assistant Examiner U.S. Cl. X.R. 259-1; 165--84 

